BATOCRINID A. 513 
Another small species of the type of A. brevis, but its calyx shorter and of 
somewhat different form, being about twice as wide as high, and pyramidal 
in outline. Dorsal cup sharply pentangular and distinctly flattened at the 
bottom. When placed on end, it rests upon the costals, the basals and radials 
forming a shallow, funnel-shaped concavity, and the distichals bending 
slightly upward. The costals and distichals curve to the sides, so as to 
form a depression at the interradial spaces, and each plate has a narrow, 
transverse, angular ridge. The suture lines are distinctly grooved. 
Radials rapidly spreading; their upper faces twice as wide as their 
lower, the upper end thickened, corresponding to the transverse ridges 
of the brachials. First costals very short, more than twice as wide as 
long; the second a little wider and longer in proportion. Distichals almost 
as short as the free arm plates; the second considerably wider than the first, 
and followed by two series of arm plates, of which the two inner series of the 
ray interlock with the second free plate, 2. e. fourth plate from the axillary. 
Arm facets large, confluent, and those of adjoining rays almost in contact. 
Arms ten, massive at the bases, quite thin at the extremities; composed of 
two rows of short parallel joints, with transverse, obscurely angular ridges. 
First interbrachials large, attenuate at the upper end, their surfaces convex ; 
the two of the second range long and extremely narrow. The first anal, 
which is fully as long but not as wide as the radials, is followed by three 
elongate plates, and these by a large number of irregular pieces, forming 
a slightly rounded, ridge-like elevation, with a groove at each side. Anus 
close to the posterior oral, opening out obliquely upward. Ventral disk 
depressed pyramidal ; the orals and radial dome plates distinctly convex, the 
interambulacrals almost flat. 
Horizon and Locality. — Same as last. 
Types in the (Worthen) Illinois State collection, and in the University 
Museum at Ann Arbor, Mich. . 
Agaricocrinus gracilis M. and W. 
Plate XLI. Figs. 8a, b,c. 
1861. Mexrx and Wortuen; Proceed. Acad. Nat. Sci. Phila., p. 135. 
1881. W. and Sp.; Revision Paleocr., Part II., p. 112. 
Somewhat smaller than A. brevis; the calyx wider than high; in its 
ventral aspect decidedly pentangular with concave sides. Dorsal cup de- 
65 
